59 lines
1.1 KiB
C
59 lines
1.1 KiB
C
///////////////////////////////////////////////////////////////////////////////
|
|
//
|
|
/// \file crc64_small.c
|
|
/// \brief CRC64 calculation (size-optimized)
|
|
//
|
|
// Author: Lasse Collin
|
|
//
|
|
// This file has been put into the public domain.
|
|
// You can do whatever you want with this file.
|
|
//
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
|
|
#include "check.h"
|
|
|
|
|
|
static uint64_t crc64_table[256];
|
|
|
|
|
|
#ifdef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
|
|
__attribute__((__constructor__))
|
|
#endif
|
|
static void
|
|
crc64_init(void)
|
|
{
|
|
static const uint64_t poly64 = UINT64_C(0xC96C5795D7870F42);
|
|
|
|
for (size_t b = 0; b < 256; ++b) {
|
|
uint64_t r = b;
|
|
for (size_t i = 0; i < 8; ++i) {
|
|
if (r & 1)
|
|
r = (r >> 1) ^ poly64;
|
|
else
|
|
r >>= 1;
|
|
}
|
|
|
|
crc64_table[b] = r;
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
|
|
extern LZMA_API(uint64_t)
|
|
lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc)
|
|
{
|
|
#ifndef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
|
|
mythread_once(crc64_init);
|
|
#endif
|
|
|
|
crc = ~crc;
|
|
|
|
while (size != 0) {
|
|
crc = crc64_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
|
|
--size;
|
|
}
|
|
|
|
return ~crc;
|
|
}
|